Subpixel wear compensation for graphical displays

ABSTRACT

A graphical display device includes a plurality of color-specific subpixels spatially distributed across a display region. Subpixel wear compensation is performed for some or all of the color-specific subpixels. For each color-specific subpixel, the compensation may include sampling one or more display signals directed to the color-specific subpixel to obtain a time-series of sampled values. The compensation may further include storing, in non-volatile storage, compensation data for the color-specific subpixel derived from the time-series of sampled values. The compensation may further include driving the color-specific subpixel based on the compensation data.

BACKGROUND

Graphical display devices include a display region formed from acollection of pixels. For some graphical display devices, each pixel mayinclude two or more individually addressable subpixels. Each subpixel ofthese multiple subpixel configurations produce light within a limitedwavelength or wavelength range that differs from the light produced byother subpixels of the same pixel. For example, each pixel of agraphical display device may include red, green, and blue lightgenerating subpixels.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

A graphical display device includes a plurality of color-specificsubpixels spatially distributed across a display region. Subpixel wearcompensation is performed for some or all of the color-specificsubpixels. For each color-specific subpixel, the compensation mayinclude sampling one or more display signals directed to thecolor-specific subpixel to obtain a time-series of sampled values. Thecompensation may further include storing, in non-volatile storage,compensation data for the color-specific subpixel derived from thetime-series of sampled values. The compensation may further includedriving the color-specific subpixel based on the compensation data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram depicting features of an example graphicaldisplay device.

FIG. 2 is a flow diagram depicting an example method of compensating forsubpixel wear in a graphical display device.

FIG. 3 is a schematic diagram depicting additional aspects ofcompensating for subpixel wear in a graphical display device.

FIG. 4 is a schematic diagram depicting an example computing system thatincludes a graphical display device and a host computing device, amongother system components.

FIG. 5 is a schematic diagram depicting an example computing system.

DETAILED DESCRIPTION

The subject matter of the present disclosure is directed to compensatingfor wear on a per subpixel basis within a graphical display device. Thedisclosed wear compensation techniques may be used to digitally correctfor a reduction in luminance per sub-pixel on a color-by-color basisthat may otherwise adversely affect the perceived brightness anduniformity of the display. Without such compensation, for example, auniformity of the display, in terms of luminance and color, may bereduced over time due to differences in use and wear characteristicsamong color-specific subpixels. The disclosed wear compensationtechniques may be implemented at pixel clock rate in a timing controllerof a graphical display device, as a non-limiting example. The disclosedtechniques further enable relatively slower updates to accumulatedsubpixel wear (e.g., at a host computing device).

FIG. 1 is a schematic diagram depicting features of an example graphicaldisplay device 100. Graphical display device 100 includes a displayregion 110 including a plurality of pixels that are spatiallydistributed across display region 110. For example, display region 110may include a geometric array of thousands, millions, or more pixels.Graphical display device 100 may take the form of an LED or OLEDdisplay, as non-limiting examples.

A sub-region 112 of display region 110 is expanded within FIG. 1 todepict additional details, including individual pixel 114 arranged amonga plurality of neighboring pixels of the sub-region. Pixel 114 is alsofurther expanded within FIG. 1 to depict additional details, including aplurality of subpixels of pixel 114. The term “subpixel” refers to anindividually addressable subunit of a pixel. A pixel may include a setof two or more color-specific subpixels in which each color-specificsubpixel of the pixel generates light within a limited wavelength orwavelength range that differs from the light generated by at least oneother color-specific subpixel of the set.

As depicted in FIG. 1, pixel 114 includes three color-specific subpixelsin which a first subpixel 116 corresponds to a red subpixel, a secondsubpixel 118 corresponds to a green subpixel, and third subpixel 120corresponds to a blue subpixel. It will be understood that a pixel mayinclude any suitable quantity of color-specific subpixels that supporttwo, three, four, five, or more different wavelengths or wavelengthranges of illumination. Within this context, the term “color” may referto electromagnetic radiation within the human-visible wavelength rangeincluding white light, as well as infrared and other near-visiblewavelength ranges (e.g., ultra-violet). In some implementations, two ormore subpixels may support the same color (e.g., a pixel may include twogreen subpixels). Each pixel of display region 110 may include the samequantity and/or geometric arrangement of color-specific subpixels.Accordingly, graphical display device 110 may include a plurality ofcolor-specific subpixels of two or more different wavelengths orwavelength ranges that are spatially distributed across display region110 of the graphical display device.

Over time, as a subpixel is driven to generate light and therebyilluminate the display region, the subpixel may experience wear in theform of reduced luminance output by the subpixel per unit power input tothe subpixel. A magnitude of subpixel wear may be dependent upon amagnitude of power input to the subpixel and a duration of that powerinput. For example, a subpixel will typically experience greater wearover a given period of time if the subpixel is driven by a greater powerinput to provide a higher level of illumination as compared to a lowerpower input providing a lower level of illumination. Accordingly, amagnitude of subpixel wear may be characterized by the integral of afunction that describes a relationship between time and power input tothe subpixel.

FIG. 1 further depicts a non-limiting example of subpixel wear over timefor example subpixel 116. At an initial time (T.0), subpixel 116 isdriven at a given power input that corresponds to 90% of its initialmaximum luminance. As time progresses over which subpixel 116 is drivento provide illumination that is either constant or variable (as visuallydepicted from time T.0 to T.1 to T.2 to T.N, etc.), the subpixel'sluminance is gradually reduced when driven by the same power input. Forexample, at time T.1, subpixel 116 provides only 89% of its originalmaximum luminance as compared to the initial 90% for the same powerinput. At T.2, subpixel 116 provides only 88% of its original maximumluminance as compared to the initial 90% for the same power input. Attime T.N, subpixel 116 provides only 85% of its original maximumluminance as compared to the initial 90% for the same power input.

Subpixel wear may further be color-dependent. For example,color-specific subpixel 116 corresponding to a first wavelength orwavelength range may exhibit a different rate of subpixel wear in termsof a reduction in luminance for a given power input as compared tocolor-specific subpixels 118 or 120 corresponding to differentwavelength or wavelength ranges. Therefore, over time, a graphicaldisplay device that includes a plurality of color-dependent subpixels oftwo or more different wavelengths or wavelength ranges may exhibitvariation in luminance and/or color across the display region.

In some scenarios, the appearance of subpixel wear in the form ofreduced luminance per power input may be reduced or eliminated bycompensating for subpixel wear on a color-by-color basis throughadjustment of the input power driving the subpixels. For example, apower input to subpixel 116 at time T.N may be adjusted to increase theluminance of the subpixel to or towards the original luminance value of90%, thereby reducing variations in luminance and/or color across thedisplay region that may otherwise develop over time.

However, in some scenarios, fully compensating for subpixel wear acrossa display region of pixels may not be possible or may be undesirable.Accordingly, the appearance of subpixel wear may be reduced by scaling alevel of compensation applied to power input to the subpixels over thedisplay region to provide a more uniform luminance and/or to reducecolor variation across the display region that may otherwise developover time.

FIG. 2 is a flow diagram depicting an example method 200 of compensatingfor subpixel wear in a graphical display device. Method 200 may beperformed in connection with a graphical display device having aplurality of color-specific subpixels that are spatially distributedacross a display region of the graphical display device. For example,method 200 may be performed in connection with graphical display device100 of FIG. 1 to compensate for subpixel wear.

Method 200 or portions thereof may be performed by a variety ofdifferent computing platforms depending on implementation. Asnon-limiting examples, method 200 may be performed entirely by acomputing platform of the graphical display device in a display-basedimplementation, entirely by a computing platform of the host computingdevice connected to the graphical display device in a host-basedimplementation, or collectively by the graphical display device and thehost computing device in a localized distributed implementation. Asanother non-limiting example, method 200 may be performed by a computingplatform of a remote computing device (e.g., a network service)connected to the graphical display device or a host computing device viaa communications network in a network-based implementation, or may becollectively performed by computing platforms of the remote computingdevice and the graphical display device and/or host computing device ina highly distributed network-based implementation.

Method 200 is described with reference to an individual color-specificsubpixel of a graphical display device. Furthermore, method 200 orportions thereof may be performed for each color-specific subpixel of asubset of the plurality of color-specific subpixels of the graphicaldisplay device. This subset may refer to all or fewer than all subpixelsof a particular color (e.g., wavelength or wavelength range), forexample. In an example, method 200 or portions thereof may be performedfor each and every color-specific subpixel of the graphical displaydevice on a color-by-color basis. Accordingly, in a more comprehensiveimplementation, method 200 may be performed for each and every subpixelof the graphical display device, whereas in a less comprehensiveimplementation, method 200 may be performed for only some of thesubpixels of the graphical display device.

For the color-specific subpixel, at 210, the method includes samplingone or more display signals 212 directed to the color-specific subpixelto obtain a time-series of sampled values 214. Each sampled value of thetime-series of sampled values 214 may correspond to a display value ofthe display signal at which the color-specific subpixel is driven toprovide illumination. Each sampled value of the time-series of sampledvalues 214 may have a magnitude that is associated with an identifier(e.g., address) of the color-specific subpixel. Display signals 212 maycorrespond to uncompensated or compensated display signals that areactually used to drive the color-specific subpixel. These displaysignals define a power input to the color-specific subpixel, which inturn defines a luminance of the color-specific subpixel. In at leastsome implementations, the graphical display device may communicate thedisplay value or information describing the display signal driving thecolor-specific subpixel to a host computing device for sampling and/oraccumulation of sampled values.

Sampling display signals 212 may be performed across multiple sessionsof the graphical display device. As an example, display signals 212 maybe sampled over each and every session of the graphical display devicefrom its inception so that sampled values 214 provide a historicalrecord of use of the color-specific subpixel over the entire lifespan ofthe graphical display device. Sampling of display signals 212 may beperformed at predetermined sampling intervals, which may be time and/ordisplay frame dependent (every frame, once per 10 frames, once persecond, once per minute, once per hour, etc.), or at random samplingintervals depending on implementation.

At 216, the method includes storing the sampled values 214 incomputer-readable storage, which may take the form of non-volatilestorage or volatile storage of the graphical display device, a hostcomputing device connected to the graphical display device, or a remotecomputing device connected to the graphical display device or hostcomputing device via a communications network. Volatile storage may beused, for example, within implementations where a computing platform ofthe graphical display device or a host computing device retains thesampled values during runtime. By contrast, non-volatile storage may beused to persistently retain the sampled values, even across multiplesessions involving start-up and shutdown of the computing platform, forexample. In at least some implementations, a computing platform (e.g.,of the graphical display device or host computing device) may store thesampled values in non-volatile storage, and may provide those sampledvalues to another computing platform (e.g., the other of the graphicaldisplay device or host computing device) during runtime.

For the color-specific subpixel, at 218, the method includes combiningtwo or more initially sampled values of the time-series of sampledvalues 214 to obtain accumulated value 220 for the color-specificsubpixel. As a first example, combining the two or more sampled valuesat 218 may include summing the magnitudes of the two or more sampledvalues to obtain accumulated value 220. As a second example, combiningthe two or more sampled values at 218 may include averaging the two ormore sampled values to obtain accumulated value 220. As a third example,combining the two or more sampled values at 218 may include determiningaccumulated value 220 as an integral of a function described by amagnitude of the sampled values and their respective time of samplingwithin the time-series of sampled values. Still other suitablecombinations of sampled values may be used to obtain an accumulatedvalue.

Some subpixel technologies or configurations may experience wear thatexhibits a non-linear relationship to power input. Accordingly, eachsampled value may be scaled according to an accumulation scalingfunction to obtain a linearized form of the sampled value prior to beingcombined with other sampled values at 218. The accumulation scalingfunction may be predefined and may reside in computer-readable storage,or may be provided to the computing platform from a remote source basedon an identity of the graphical display device. Furthermore, theaccumulation scaling function may be color-dependent such that eachwavelength or wavelength range of color-specific subpixels has acolor-specific accumulation scaling function. For example, in a pixelhaving red, green, and blue color-specific subpixels, three differentcolor-specific accumulation scaling functions may be applied.

At 222, the method includes storing accumulated value 220 incomputer-readable storage, which may take the form of non-volatilestorage or volatile storage of the graphical display device, a hostcomputing device connected to the graphical display device, or a remotecomputing device connected to the graphical display device or hostcomputing device via a communications network. Volatile storage may beused, for example, within implementations where a computing platform ofthe graphical display device or a host computing device retains theaccumulated during runtime. By contrast, non-volatile storage may beused to persistently retain the accumulated value, even across multiplesessions involving start-up and shutdown of the computing platform, forexample. In at least some implementations, a computing platform (e.g.,of the graphical display device or host computing device) may store theaccumulated value in non-volatile storage, and may provide theaccumulated value to another computing platform (e.g., the other of thegraphical display device or host computing device) during runtime.

The method at 218 may further include updating accumulated value 220 bycombining one or more subsequently sampled values of the time-series ofsampled values 214 with the accumulated value representing thecombination of two or more initially sampled values of the time-seriesof sampled values 214. For example, accumulated value 220 stored at 222may be updated to reflect the combination of at least one subsequentlysampled value with the two or more initially sampled values. Thecombination of one or more subsequently sampled values with accumulationvalue 220 may include the previously described summation, average, orintegral, for example. The accumulation scaling function, if applied tothe initially sampled values, may be similarly applied to thesubsequently sampled values prior to being combined with the accumulatedvalue as previously described. This process may be repeated for eachsubsequently sampled value of the time-series of sampled values 214. Assuch, accumulated value 220 may represent a history of use of thecolor-specific subpixel over the entire operational time of thegraphical display device.

In at least some implementations, accumulated value 222 may beassociated with one or more metadata values that identifies a time range(e.g., time counter) and/or a quantity of the sampled values (e.g.,sample counter) that were previously combined to obtain the accumulatedvalue 220. These metadata values may be used to consistently combinesubsequently sampled values with previously combined sampled values ofthe accumulated value. For example, a metadata value that indicates atime range and/or quantity of previously combined sampled values may beused at 218 to weight the contribution of a subsequently sampled valueto the updated accumulated value. The time range indicated by themetadata value may correspond to the entire operational time of thegraphical display device (e.g., time counter) or may correspond to atime range (e.g., sampling rate) of each individual sampled value,depending on implementation.

At 224, the method includes deriving compensation data for thecolor-specific subpixel from the time-series of sampled values 214.Compensation data for a color-specific subpixel may include or otherwiserefer to a correction value for the color-specific subpixel that may beused to augment the power input to the color-specific subpixel duringoperation to correct for wear. The correction value is described infurther detail with reference to FIG. 3, and may be referred to as thesubpixel multiplication memory (SPMM) value. Compensation data for acolor-specific subpixel may further include or otherwise refer to acorrection factor that is dependent upon the correction value. Thecorrection factor is also described in further detail with reference toFIG. 3, and may be referred to as the subpixel memory equivalent (SPMEQ)value.

For each color-specific subpixel of the first subset, compensation datamay be derived from the time-series of sampled values based on a firstsubpixel wear model. For other subsets of color-specific subpixels,compensation data may be derived from a time-series of sampled valuesbased on a second subpixel wear model that differs from the firstsubpixel wear model. For example, the first subset may correspond tocolor-specific subpixels of a first color, and the second subset maycorrespond to color-specific subpixels of a second color that exhibitssubpixel wear at a different rate than the first color. Here, the firstsubpixel wear model may define a first relationship between a magnitudeof an accumulated value of the time-series of sampled values forcolor-specific subpixels of the first subset and the compensation datato be derived from the time-series of sampled values for thecolor-specific subpixels of the first subset. Similarly, the secondsubpixel wear model may define a second relationship, that differs fromthe first relationship, between a magnitude of an accumulated value ofthe time-series of sampled values for color-specific subpixels of thesecond subset and the compensation data to be derived from thetime-series of sampled values for the color-specific subpixels of thesecond subset. A different subpixel wear model may be used for eachcolor of subpixels supported by the graphical display device.

For example, at 226, the method includes deriving a correction value 228for the color-specific subpixel from accumulated value 220. Correctionvalue 228 represents a magnitude of correction that is to be applied tothe color-specific pixel to compensate for wear. As accumulated value220 increases over time due to use of the color-specific subpixel,correction value 228 may also increase to reflect the need for greatercompensation to be applied to the color-specific subpixel.

In at least some implementations, a correction scaling function maydefine a relationship between accumulated value 220 and correction value228. Here, the correction scaling function is a non-limiting example ofa subpixel wear model discussed above. The correction scaling functionmay be predefined and may reside in computer-readable storage, or may beprovided to the computing platform from a remote source based on anidentity of the graphical display device. Furthermore, the correctionscaling function may be color-dependent in which each wavelength orwavelength range of color-specific subpixel of the graphical displaydevice has a corresponding correction scaling function for thatwavelength or wavelength range. For example, in a pixel having red,green, and blue color-specific subpixels, three different color-specificcorrection scaling functions may be applied to accumulated valuesobtained for the red, green, and blue color-specific subpixels.

As previously described, correction value 228 may be based onaccumulated value 220 for the color-specific subpixel, and may befurther based on a rebalancing input 232 representing accumulated valuesor correction values of other color-specific subpixels of the samesubset of color-specific pixels. Within this context, rebalancing amongsome or all of the color-specific subpixels of the subset may beperformed to obtain a rebalanced correction value 228 for thecolor-specific subpixel. As an example, the subset may correspond tosome or all of the color-specific subpixels of the graphical displaydevice of a particular wavelength or wavelength range (e.g., redsubpixels).

Continuing with this example, correction value 228 may be rebalancedamong other correction values for other color-specific subpixels of thesubset to maximize a total quantity of color-specific subpixels having arebalanced correction value that corresponds to a target compensationvalue (e.g., unity or uncompensated) among the subset of color-specificsubpixels. This rebalancing approach may limit the extent to whichsaturation is used to compensate for wear of color-specific subpixels.

For example, the compensation data (e.g., rebalanced compensation value)may be applied to an input display value to provide signal gain orsignal attenuation to the input display value to obtain a compensateddisplay signal. Here, rebalancing the signal gain or signal attenuationprovided to the input display value may be used to increase or maximizea quantity of color-specific subpixels of the subset that have a targetcompensation value that does not introduce signal gain or signalattenuation.

At 230, the method includes storing correction value 228 incomputer-readable storage, which may take the form of non-volatilestorage or volatile storage of the graphical display device, a hostcomputing device connected to the graphical display device, or a remotecomputing device connected to the graphical display device or hostcomputing device via a communications network. Volatile storage may beused, for example, within implementations where a computing platform ofthe graphical display device or a host computing device retains thecompensation value during runtime. By contrast, non-volatile storage maybe used to persistently retain the compensation value, even acrossmultiple sessions involving start-up and shutdown of the computingplatform, for example. In at least some implementations, a computingplatform (e.g., of the graphical display device or host computingdevice) may store the compensation value in non-volatile storage, andmay provide the compensation value to another computing platform (e.g.,the other of the graphical display device or host computing device)during runtime. Depending on implementation, compensation value 228stored at 230 may include the rebalanced compensation value or aninitial compensation value that is not rebalanced relative to othercolor-specific subpixels of the subset.

At 234, the method includes driving the color-specific subpixel based onthe compensation data for the color-specific subpixel. As previouslydescribed, the compensation data may include correction value 228, ineither rebalanced or initial form. In at least some implementations, asubpixel scaling function 236 executed by a computing system receives anuncompensated input display value 238 for the color-specific subpixeland correction value 228 for the color-specific subpixel. The subpixelscaling function 236 applies correction value 228, as a correctionfactor, to uncompensated input display value 238 to obtain a compensateddisplay value 240.

In an example, an input display value is generated for eachcolor-specific subpixel of the subset of color-specific subpixels (aswell as all other subpixels of the display region) by a host computingdevice connected to the graphical display device. For eachcolor-specific subpixel of the subset, the input display value isgenerated by the host computing device, the compensation data is appliedto the input display value to obtain a compensated display value, andthe color-specific subpixel is driven (e.g., by a power input) with acompensated display signal that is based on the compensated displayvalue.

Accordingly, the color-specific subpixel is driven responsive tocompensated display value 240 to provide a driven color-specificsubpixel, as indicated at 242. Here, driving the color-specific subpixelbased on the compensation data may include driving the color-specificsubpixel with a compensated display signal that is based on thecompensated display value. For example, compensated display value 240may take the form of a control signal that defines power input to beapplied to the color-specific subpixel by way of the compensated displaysignal. Accordingly, differences between compensated display value 240and uncompensated input display value 238 correspond to differences inpower input to the color-specific subpixel, which in turn defines alevel of luminance produced by that color-specific subpixel.

Correction value 228 may be mapped to a corresponding correction factorto be applied to uncompensated input display value 238 by subpixelscaling function 236. As an example, subpixel scaling function 236 mayaccess a look-up table, map, or other suitable relationship that definesa mapping between a range of available correction values and a range ofavailable correction factors. The relationship between correction valueand correction factor may be predefined and may reside in localcomputer-readable storage, or may be provided to the computing platformfrom a remote source based on an identity of the graphical displaydevice. Furthermore, this relationship may be color-dependent in whicheach wavelength or wavelength range of color-specific subpixel of thegraphical display device has a corresponding relationship betweencorrection value and factor for that wavelength or wavelength range. Forexample, in a pixel having red, green, and blue color-specificsubpixels, three different relationships may be defined betweencorrection value and correction factor for the red, green, and bluecolor-specific subpixels. The subpixel scaling function will bedescribed in further detail with reference to FIG. 3.

FIG. 3 is a schematic diagram depicting additional aspects ofcompensating for subpixel wear in a graphical display device. Theaspects depicted in FIG. 3 may be incorporated into method 200 and/ormay be implemented apart from method 200. For example, the subpixelscaling functions described with reference to FIG. 3 are non-limitingexamples of subpixel scaling function 236 of FIG. 2.

Within FIG. 3, a hardware machine of a computing platform of thegraphical display device is capable of providing per sub-pixel wearcompensation at pixel clock rate. The computing platform of thegraphical display device includes a correction memory structure referredto as subpixel multiplication memory (SPMM). In FIG. 3, the SPMM takesthe form of an SPMM buffer 314, as a non-limiting example.

The SPMM can be written to and read from using a common commandinterface 310, such as MIPI, DisplayPort, or HDMI, as non-limitingexamples. A new MIPI, DisplayPort, or HDMI command may be defined toenable for updates of the SPMM. Alternatively, the SPMM could be updatedusing a virtual channel. Alternatively the SPMM could be updated using adedicated interfaces such as parallel, I2C, SPI, etc. Values written tothe SPMM may be referred to as SPMM values that correspond to thepreviously described correction values of method 200 of FIG. 2.

In at least some implementations, the SPMM is architecturally similar tothe frame memory used in a full frame buffer or partial frame buffer ofa timing controller. The SPMM provides per-subpixel correction values toa sub-pixel scaling function in the display controller data path toapply a correction factor to each sub-pixel. The correction valueswritten to the SPMM may be calculated outside of the timing controllerat a relatively slow rate by a sampling algorithm implemented by acomputing platform located off-board the graphical display device toaccumulate wear statistics per pixel (e.g., the accumulated value). Forexample, an algorithm implemented at a host computing device may be usedto calculate a correction value per sub-pixel based on wear modelsdetermined per model of graphical display device. Alternatively, atiming controller processing or hardware machine may be used tocalculate the correction values to be stored in the SPMM.

However, since subpixel wear is a relatively slow moving process, thehost computing device is able to slowly update the SPMM, as newcorrection values are calculated. These new correction values may bequeued, while the display is active in a smaller shadow memory structure312. The new correction values may be committed to the correction memorystructure SPMM from the shadow memory structure during the displaynon-active time (e.g., blanking). However, in some implementations, theSPMM values are loaded into the SPMM buffer during startup or booting ofthe host computing device. Accordingly, elements 310 and 312 of FIG. 3may be omitted in at least some implementations. Alternatively, thecorrection values to be written to the SPMM may be calculated outside ofthe host computing device, in a cloud-based network-connected computingplatform of a remote computing device, thereby enabling a lower costhost and/or reduction in calculations performed at the host.

A state machine or processing function referred to as the subpixelscaling function implemented by a computing platform of the graphicaldisplay device may coordinate the fetching of SPMM values from thesubpixel multiplication memory. The subpixel scaling function previouslydescribed with reference to element 236 of FIG. 2 is depicted inmultiple instances in FIGS. 3 at 322, 332, 342, and 352. Each instanceof the subpixel scaling function receives input values in the form of asubpixel value (SP1, SP2, SP3, SP4, etc.), also referred to as anuncompensated display value in the method of FIG. 2, and an SPMM valuefor that color-specific subpixel, and outputs a corrected subpixel value(CSP1, CSP2, CSP3, CSP4, etc.), also referred to as a compensateddisplay value in the method of FIG. 2. Within FIG. 3, uncompensatedsubpixels are represented schematically at 320, 330, 340, and 350, andtheir compensated subpixel equivalents are represented schematically at324, 334, 344, and 354.

The architecture of the SPMM may be partitioned to support one, two, ormore pixel pipelines depending on the internal architecture of thetiming controller. The subpixel scaling function may implement asaturation multiplication function that receives an N-bit pixel as oneoperand and an M-bit multiplication function as the second operand fromthe SPMM. The size of N may be determined by system requirements, butmay, for example, be in the range of 6, 8, 10 or more bits. Thecorrection value applied at the subpixel level corresponds to the M-bitvalue which can be less than the number of bits (N) used to encode thevalue of the sub-pixel. The size of M may be chosen to simultaneouslysatisfy the performance requirements of the system, wear characteristicof the pixels, and lifetime requirement for the graphical displaydevice.

The behavior of the subpixel scaling function may be representedmathematically by the following expression: CSP=SP X SPMEQ, wherein X issaturating multiplication, CSP refers to compensated subpixel, SP refersto subpixel value, and SPMEQ refers to subpixel multiplicationequivalent which is also referred to as the correction factor.

A non-limiting example mapping of SPMM to SPMEQ, using M=8, includes:0x00=0.5000, 0x7F=1.0000, 0x80=1.0078 (saturating), 0xFF=2.0000(saturating). As another non-limiting example mapping of SPMM to SPMEQ,using M=8, includes: 0x00=0.2500, 0x4F=1.0000, 0x50=1.0078 (saturating),0x7F=2.0000 (saturating), 0xFF=4.0000 (saturating). As anothernon-limiting example mapping of SPMM to SPMEQ, using M=2, includes:2′b00=0.5, 2′b01=1.0, 2′b10=1.5 (saturating), 2′b11=2.0 (saturating). Ineach of the above examples, 1.0 represents unity or an uncompensateddisplay signal. It will be understood that these above non-limitingexamples are provided for illustrative purposes, and that other mappingsmay be used depending on implementation and the overall granularity ofcompensation factors.

In view of the above, if M is set to equal a value of 0.0 and SPMEQ isset to equal a value of 1.0, compensation would not be applied to thesubpixel. The number of bits used to represent the characteristic andthe mantissa of the SPMEQ may be configured during design of thegraphical display device to optimally meet the requirements of thesystem. In at least some implementations, the SPMM to SPMEQ mapping maybe fixed in hardware to provide a cost efficient implementation.Alternatively, a look up table or other suitable predeterminedrelationship may be used, which allows the mapping of SPMM to SPMEQ tobe dynamically or statically configured. The look up table, for example,could explicitly define every possible SPMM to SPMEQ mapping. The lookup table could also be a sparse mapping where not every value isexplicitly defined. Intermediate values not found in the table could begenerated by interpolation.

FIG. 4 is a schematic diagram depicting a non-limiting example of acomputing system 400. Computing system 400 includes a graphical displaydevice 410 having a plurality of color-specific subpixels spatiallydistributed across a display region 412 of the graphical display device.Graphical display device 410 is a non-limiting example of previouslydescribed graphical display device 100 of FIG. 1.

In this example, display region 412 includes an array of pixels in whicheach pixel includes two or more color-specific subpixels. Example pixel414, which includes three color-specific subpixels 416, 418, and 420, isrepresentative of each pixel of display region 412. Color-specificsubpixels 416, 418, and 420 correspond to different wavelength orwavelength ranges in this example. Accordingly, pixel 414 has threedifferent color-specific subpixels in this example. Furthermore, in thisexample, color-specific subpixel 418 has a different configuration thancolor-specific subpixels 416 and 420. For example, color-specificsubpixel 418 may be larger and/or may have a different shape thancolor-specific subpixels 416 and 420. Furthermore, in someimplementations, a pixel may include two or more color-specificsubpixels of the same wavelength or wavelength range.

Graphical display device 410 further includes a display-based computingplatform 422 having a logic machine 424 and a data storage machine 426.As an example, logic machine 424 and data storage machine 426 maycollectively implement the previously described subpixel scalingfunction 236 of FIG. 2. Logic machine 424 and data storage machine 426may collectively implement or take the form of a timing controllerand/or a display controller of the graphical display device as will bedescribed in further detail with reference to FIG. 3. Aspects of logicmachine 424 and data storage machine 426 will be described in furtherdetail with reference to FIG. 5.

Graphical display device 410 further includes a host interface 428 tointerface with a host device. Host interface 428 may supportcommunication of electrical power, electrical ground, and/or data over acommunications link 430 with a host computing device. Computing system400 further includes an example of a host computing device 432interfacing with graphical display device 410 as indicated schematicallyby communications link 430. Graphical display device 410 may bephysically integrated with host computing device 432 in a commonenclosure (e.g., a smart phone or tablet form-factor). Alternatively,graphical display device 410 may be a peripheral display devicephysically separated from host computing device 432, such that eachdevice may have a separate enclosure.

Communications link 430 may take the form of one or more physical links(e.g., wires, electrical traces, or fiber optics) and/or one or morewireless communications links. Communications link 430 may represent oneor more data pathways, one or more electrical power pathways, one ormore electrical ground pathways, etc. Communications link 430 mayutilize any suitable protocol or set of protocols to facilitate theexchange of data, electrical power, and/or electrical ground overcommunications link 430. Communications link 430 may be implemented onhost computing device 432 via a display interface 434 and on graphicaldisplay device 410 via host interface 428.

In some implementations, display interface 434 and host interface 428may each include a physical electrical connector having one or moreelectrically conductive pins or contacts. Here, each physical electricalconnector may establish communications link 430 by interfacing with eachother, or optionally via an intermediate cable or set of cables havingcorresponding physical electrical connectors. Non-limiting examples ofphysical electrical connectors for peripheral graphical display devicesinclude DisplayPort, Mini DisplayPort, HMDI, USB, etc. However, one ormore physical electrical conductive links of communications link 430 maybe hardwired or otherwise permanently integrated between graphicaldisplay device 410 and host computing device 432, such as within thecontext of a fully integrated system within a common enclosure.

Host computing device 432 includes a primary computing platform 434 thatincludes a logic machine and a data storage machine. Host computingdevice 432 may further include a graphics platform 436, which refers toa special-purpose computing platform of the host computing device thatmay be used within the context of graphics processing. For example,graphics platform 436 may take the form of a graphics processing unit(GPU). Graphics platform 436 may include a logic machine and a datastorage machine, as will be described in further detail with referenceto FIG. 5.

Host computing device 432 may further include a network interface 438 bywhich the host computing device communicates with other computingdevices via a communications network 440. For example, host computingdevice 432 may communicate with remote computing device 442 to provideor obtain display specific data 460 from off-board the host computingdevice.

Display specific data 460 may include or may be associated with adisplay identifier 462 that identifies graphical display device 410within a domain of graphical display devices. Display identifier 462 mayrefer to a hardware identifier or a firmware identifier of graphicaldisplay device 410. Display identifier 462 may be communicated bygraphical display device 410 to host computing device 440, and may beused by host computing device 440 to retrieve other forms ofdisplay-specific data 460 from remote sources or provide other forms ofdisplay-specific data 460 to remote sources, such as remote computingdevice 452. Likewise, other host computing devices (e.g., 454) may usedisplay identifier 462 to retrieve or provide other forms ofdisplay-specific data 460 for graphical display device 410, therebyenabling measurements of subpixel wear to be tracked and maintainedacross multiple host computing devices.

Display-specific data 460 may further include an accumulated value 464for each subpixel of the graphical display, which is a non-limitingexample of previously described accumulated value 220 of FIG. 2.Display-specific data 460 may further include compensation data 466 foreach subpixel of the graphical display, including a correction value 468and/or a correction factor 470 for each subpixel of the graphicaldisplay. Correction value 468 a non-limiting example of previouslydescribed correction value 228 of FIG. 2. Display-specific data 460 mayfurther include scaling and relationship data 472, which may include thepreviously described accumulation scaling function, correction scalingfunction, and correction value (e.g., SPMM value) to correction factor(e.g., SPMEQ value) mapping of method 200 of FIG. 2.

The broken lines within FIG. 4 depict numerous non-limiting examples ofwhere display-specific data 460 may be stored. In at least someimplementations, the accumulated value and/or the compensation data foreach subpixel of the graphical display device may be stored innon-volatile storage of the host computing device connected to thegraphical display device. Additionally or alternatively, the accumulatedvalue and/or the compensation data for each subpixel of the graphicaldisplay device may be stored in non-volatile storage of the graphicaldisplay device. Additionally or alternatively, the accumulated valueand/or compensation data for each subpixel of the graphical displaydevice may be stored in the non-volatile storage of a remote computingdevice connected to the host computing device via a network.

In a non-limiting example of a distributed implementation, the displaysignals driving the color-specific subpixels are sampled by the hostcomputing device to obtain a time-series of sampled values, and thecompensation data is derived from the time-series of sampled values bythe host computing device for each color-specific subpixel of a subset(or of the entire graphical display device). For each color-specificsubpixel of the subset, the compensation data is transmitted from thehost computing device to the graphical display device, the compensationdata is received at the graphical display device, and the compensationdata is applied at the graphical display device to an input displayvalue received from the host computing device to obtain a compensateddisplay value. The graphical display device drives the color-specificsubpixels based on the compensation data for each subpixel with acompensated display signal for that subpixel that is based on thecompensated display value. However, in a localized implementation, theabove processes may be performed on-board the graphical display devicewith the exception of input display signals being generated by the hostcomputing device.

In at least some implementations, the methods and processes describedherein may be tied to a computing system of one or more computingdevices. In particular, such methods and processes may be implemented asa computer-application program or service, an application-programminginterface (API), a library, and/or other computer-program product.

FIG. 5 schematically shows a non-limiting example of a computing system500 that can enact one or more of the methods and processes describedabove. For example, computing system 500 may be representative ofcomputing system 400 of FIG. 4, or the various computing devices and/orcomputing platforms thereof, including host computing device 440, remotecomputing device 452, other host computing device 454, and hostcomputing device 440 in combination with graphical display device 410.Computing system 500 is shown in simplified form. Computing system 500may take the form of one or more personal computers, server computers,tablet computers, home-entertainment computers, network computingdevices, gaming devices, mobile computing devices, mobile communicationdevices (e.g., smart phone), and/or other computing devices.

Computing system 500 includes a logic machine 510 and a data storagemachine 512. Computing system 500 may optionally include a displaysubsystem 514 (e.g., an integrated or peripheral graphical displaydevice), an input subsystem, a communication subsystem, and/or othercomponents not shown in FIG. 5.

Logic machine 510 includes one or more physical devices configured toexecute instructions. For example, the logic machine may be configuredto execute instructions that are part of one or more applications,services, programs, routines, libraries, objects, components, datastructures, or other logical constructs. Such instructions may beimplemented to perform a task, implement a data type, transform thestate of one or more components, achieve a technical effect, orotherwise arrive at a desired result.

The logic machine may include one or more processors configured toexecute software instructions. Additionally or alternatively, the logicmachine may include one or more hardware or firmware logic machinesconfigured to execute hardware or firmware instructions. Processors ofthe logic machine may be single-core or multi-core, and the instructionsexecuted thereon may be configured for sequential, parallel, and/ordistributed processing. Individual components of the logic machineoptionally may be distributed among two or more separate devices, whichmay be remotely located and/or configured for coordinated processing.Aspects of the logic machine may be virtualized and executed by remotelyaccessible, networked computing devices configured in a cloud-computingconfiguration.

Storage machine 512 includes one or more physical devices configured tohold instructions executable by the logic machine to implement themethods and processes described herein. When such methods and processesare implemented, the state of storage machine 512 may betransformed—e.g., to hold different data.

Storage machine 512 may include removable and/or built-in devices.Storage machine 512 may include optical memory (e.g., CD, DVD, HD-DVD,Blu-Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM,etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive,tape drive, MRAM, etc.), among others. Storage machine 512 may includevolatile, nonvolatile, dynamic, static, read/write, read-only,random-access, sequential-access, location-addressable,file-addressable, and/or content-addressable devices.

It will be appreciated that storage machine 512 includes one or morephysical devices. However, aspects of the instructions described hereinalternatively may be propagated by a communication medium (e.g., anelectromagnetic signal, an optical signal, etc.) that is not held by aphysical device for a finite duration. Furthermore, aspects ofinstructions described herein may reside on removable media devices,such as represented schematically at 518.

Logic machine 510 and storage machine 512 may be collectively referredto as a computing platform. Aspects of logic machine 510 and storagemachine 512 may be integrated together into one or more hardware-logiccomponents. Such hardware-logic components may includefield-programmable gate arrays (FPGAs), program- andapplication-specific integrated circuits (PASIC/ASICs), program- andapplication-specific standard products (PSSP/ASSPs), system-on-a-chip(SOC), and complex programmable logic devices (CPLDs), for example.

The terms “module,” “program,” and “engine” may be used to describe anaspect of computing system 500 implemented to perform a particularfunction. In some cases, a module, program, or engine may beinstantiated via logic machine 510 executing instructions held bystorage machine 512. It will be understood that different modules,programs, and/or engines may be instantiated from the same application,service, code block, object, library, routine, API, function, etc.Likewise, the same module, program, and/or engine may be instantiated bydifferent applications, services, code blocks, objects, routines, APIs,functions, etc. The terms “module,” “program,” and “engine” mayencompass individual or groups of executable files, data files,libraries, drivers, scripts, database records, etc.

It will be appreciated that a “service”, as used herein, is anapplication program executable across multiple user sessions. A servicemay be available to one or more system components, programs, and/orother services. In some implementations, a service may run on one ormore server-computing devices. As an example, a service may providedisplay-specific data to a client host computing device or clientgraphical display device in response to a request that contains anidentifier of the graphical display device. As another example, aservice may store display-specific data received from a client hostcomputing device or client graphical display device in response to arequest that contains an identifier of the graphical display device.

When included, display subsystem 514 may be used to present a visualrepresentation of data held by storage machine 512. This visualrepresentation may take the form of a graphical user interface (GUI). Asthe herein described methods and processes change the data held by thestorage machine, and thus transform the state of the storage machine,the state of display subsystem 514 may likewise be transformed tovisually represent changes in the underlying data. Display subsystem 514may include one or more graphical display devices utilizing virtuallyany type of technology. Again, such display devices may be combined withlogic machine 510 and/or storage machine 512 in a shared enclosure 516,or such display devices may be peripheral display devices.

When included, an input subsystem may comprise or interface with one ormore user-input devices such as a keyboard, mouse, touch screen, or gamecontroller. In some embodiments, the input subsystem may comprise orinterface with selected natural user input (NUI) componentry. Suchcomponentry may be integrated or peripheral, and the transduction and/orprocessing of input actions may be handled on- or off-board. Example NUIcomponentry may include a microphone for speech and/or voicerecognition; an infrared, color, stereoscopic, and/or depth camera formachine vision and/or gesture recognition; a head tracker, eye tracker,accelerometer, and/or gyroscope for motion detection and/or intentrecognition; as well as electric-field sensing componentry for assessingbrain activity.

When included, a communication subsystem may be configured tocommunicatively couple computing system 500 with one or more othercomputing devices. Communication subsystem may include wired and/orwireless communication devices compatible with one or more differentcommunication protocols. As non-limiting examples, the communicationsubsystem may be configured for communication via a wireless telephonenetwork, or a wired or wireless local- or wide-area network. In someembodiments, the communication subsystem may allow computing system 500to send and/or receive messages to and/or from other devices via anetwork such as the Internet.

In an example, a method of compensating for subpixel wear in a graphicaldisplay device having a plurality of color-specific subpixels spatiallydistributed across a display region of the graphical display devicecomprises, for each color-specific subpixel of a subset of the pluralityof color-specific subpixels: sampling one or more display signalsdirected to the color-specific subpixel to obtain a time-series ofsampled values; storing, in non-volatile storage, compensation data forthe color-specific subpixel derived from the time-series of sampledvalues; and driving the color-specific subpixel based on thecompensation data. In this example or any other example, the methodfurther comprises, for each color-specific subpixel of the subset:combining two or more initially sampled values of the time-series ofsampled values to obtain an accumulated value for the color-specificsubpixel; and deriving the compensation data for the color-specificsubpixel from the accumulated value. In this example or any otherexample, the method further comprises: storing the accumulated value innon-volatile storage; and updating the accumulated value stored innon-volatile storage by combining one or more subsequently sampledvalues of the time-series of sampled values with the two or moreinitially sampled values. In this example or any other example, theaccumulated value is stored in the non-volatile storage of a hostcomputing device connected to the graphical display device. In thisexample or any other example, the compensation data is stored in thenon-volatile storage of the graphical display device. In this example orany other example, the compensation data is stored in the non-volatilestorage of a host computing device connected to the graphical displaydevice. In this example or any other example, the compensation data isstored in the non-volatile storage of a remote computing deviceconnected to a host computing device via a network. In this example orany other example, an input display value is generated for eachcolor-specific subpixel of the subset by a host computing deviceconnected to the graphical display device. In this example or any otherexample, the method further comprises, for each color-specific subpixelof the subset: receiving the input display value generated by the hostcomputing device; applying the compensation data to the input displayvalue to obtain a compensated display value; wherein driving thecolor-specific subpixel based on the compensation data includes drivingthe color-specific subpixel with a compensated display signal based onthe compensated display value. In this example or any other example,applying the compensation data to the input display value includesproviding signal gain or signal attenuation to the input display valueto obtain the compensated display signal. In this example or any otherexample, the method further comprises rebalancing the signal gain orsignal attenuation provided to the input display value to increase ormaximize a quantity of color-specific subpixels of the subset that havea target compensation value that does not introduce signal gain orsignal attenuation. In this example or any other example, the one ormore display signals are sampled by a host computing device, and thecompensation data is derived from the time-series of sampled values bythe host computing device for each color-specific subpixel of thesubset. In this example or any other example, the method furthercomprises, for each color-specific subpixel of the subset: receiving,from the host computing device, the compensation data at the graphicaldisplay device, applying the compensation data at the graphical displaydevice to an input display value received from the host computing deviceto obtain a compensated display value, and wherein driving thecolor-specific subpixel based on the compensation data includes drivingthe color-specific subpixel with a compensated display signal that isbased on the compensated display value. In this example or any otherexample, the subset of the plurality of color-specific subpixelsincludes a first subset of color-specific subpixels corresponding to afirst wavelength or wavelength range; and the plurality ofcolor-specific subpixels further includes a second subset ofcolor-specific subpixels corresponding to a second wavelength orwavelength range that differs from the first subset. In this example orany other example, the method further comprises, for each color-specificsubpixel of the first subset: deriving the compensation data from thetime-series of sampled values based on a first subpixel wear model; andfor each color-specific subpixel of the second subset: deriving thecompensation data from the time-series of sampled values based on asecond subpixel wear model that differs from the first subpixel wearmodel. In this example or any other example, first subpixel wear modeldefines a first relationship between a magnitude of an accumulated valueof the time-series of sampled values for color-specific subpixels of thefirst subset and the compensation data to be derived from thetime-series of sampled values for the color-specific subpixels of thefirst subset; and the second subpixel wear model defines a secondrelationship, that differs from the first relationship, between amagnitude of an accumulated value of the time-series of sampled valuesfor color-specific subpixels of the second subset and the compensationdata to be derived from the time-series of sampled values for thecolor-specific subpixels of the second subset. In this example or anyother example, the subset of the plurality of color-specific subpixelsfurther includes a third subset of color-specific subpixelscorresponding to a third wavelength or wavelength range that differsfrom the first subset and the second subset. In this example or anyother example, the first, second, and third wavelength or wavelengthranges are selected from a group comprising red, green, blue, white,infrared.

In an example, a computing system comprises: a graphical display deviceincluding: a display region having a plurality of color-specificsubpixels spatially distributed across the display region; a datastorage machine including a buffer; and a logic machine programmed withinstructions to: for each color-specific subpixel of a subset of theplurality of color-specific subpixels: receive compensation data from ahost computing device connected to the graphical display device via acommunications link, the compensation data being derived from atime-series of sampled values obtained from previously sampled displaysignals directed to that color-specific subpixel, store the compensationdata in the buffer, receive, via the communications link, an inputdisplay value generated by the host computing device, apply thecompensation data to the input display signal to obtain a compensateddisplay value; and drive the color-specific subpixel with a compensateddisplay signal based on the compensated display value. In this exampleor any other example, the computing further comprises: the hostcomputing device, including: non-volatile storage; and a graphicsprocessing unit programmed to: for each color-specific subpixel of thesubset: sample display signals driving the color-specific subpixel ofthe graphical display device to obtain a time-series of sampled values;combine the time-series of sampled values to obtain an accumulatedvalue; store the accumulated value in the non-volatile storage; derivethe compensation data from the accumulated value; and transmit thecompensation data to the graphical display device. In this example orany other example, the subset of the color-specific subpixels includes afirst subset of color-specific subpixels corresponding to a firstwavelength or wavelength range; wherein the plurality of color-specificsubpixels includes a second subset of color-specific subpixelscorresponding to a second wavelength or wavelength range that differsfrom the first subset. In this example or any other example, the logicmachine is further programmed with instructions to: for eachcolor-specific subpixel of the second subset: receive secondcompensation data from the host computing device, the secondcompensation data for each color-specific subpixel of the second subsetbeing derived from a time-series of sampled values obtained from one ormore previously sampled display signals driving the color-specificsubpixel, store the second compensation data in the buffer, receive aninput display value generated by the host computing device, apply thecompensation data to the input display value to obtain a compensateddisplay value; and drive the color-specific subpixel with a compensateddisplay signal based on the compensated display value. In this exampleor any other example, the logic machine is further programmed withinstructions to: for each color-specific subpixel of the subset, applythe compensation data to the input display value to obtain a compensateddisplay value by rebalancing signal gain or signal attenuation providedto the input display value to increase or maximize a quantity ofcolor-specific subpixels of the subset that have a target compensationvalue that does not introduce signal gain or signal attenuation.

In an example, a method of compensating for subpixel wear in a graphicaldisplay device having a plurality of color-specific subpixels spatiallydistributed across a display region of the graphical display devicecomprises: for each color-specific subpixel of a subset of the pluralityof color-specific subpixels: sampling one or more display signalsdriving the color-specific subpixel to obtain a time-series of sampledvalues; combining the time-series of sampled values to obtain anaccumulated value; storing, in non-volatile storage, the accumulatedvalue; deriving a compensation data for the color-specific subpixel fromthe accumulated value; obtaining an input display value from a hostcomputing device connected to the graphical display device; applying thecompensation data to the input display value to obtain a compensateddisplay value; and driving the color-specific subpixel with acompensated display signal that is based on the compensated displayvalue; wherein the subset includes all color-specific subpixels of thedisplay region having a defined wavelength or wavelength range thatdiffers from another subset of color-specific subpixels of the displayregion.

It will be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. As such, various acts illustrated and/ordescribed may be performed in the sequence illustrated and/or described,in other sequences, in parallel, or omitted. Likewise, the order of theabove-described processes may be changed.

The subject matter of the present disclosure includes all novel andnon-obvious combinations and sub-combinations of the various processes,systems and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. A method of compensating for subpixel wear in a graphical displaydevice having a plurality of color-specific subpixels spatiallydistributed across a display region of the graphical display device, themethod comprising: for each color-specific subpixel of a subset of theplurality of color-specific subpixels: sampling one or more displaysignals directed to the color-specific subpixel to obtain a time-seriesof sampled values; storing, in non-volatile storage, compensation datafor the color-specific subpixel derived from the time-series of sampledvalues; and driving the color-specific subpixel based on thecompensation data.
 2. The method of claim 1, further comprising: foreach color-specific subpixel of the subset: combining two or moreinitially sampled values of the time-series of sampled values to obtainan accumulated value for the color-specific subpixel; and deriving thecompensation data for the color-specific subpixel from the accumulatedvalue.
 3. The method of claim 2, further comprising: storing theaccumulated value in non-volatile storage; and updating the accumulatedvalue stored in non-volatile storage by combining one or moresubsequently sampled values of the time-series of sampled values withthe two or more initially sampled values.
 4. The method of claim 3,wherein the accumulated value is stored in the non-volatile storage of ahost computing device connected to the graphical display device.
 5. Themethod of claim 1, wherein the compensation data is stored in thenon-volatile storage of the graphical display device.
 6. The method ofclaim 1, wherein the compensation data is stored in the non-volatilestorage of a host computing device connected to the graphical displaydevice.
 7. The method of claim 1, wherein the compensation data isstored in the non-volatile storage of a remote computing deviceconnected to a host computing device via a network.
 8. The method ofclaim 1, wherein an input display value is generated for eachcolor-specific subpixel of the subset by a host computing deviceconnected to the graphical display device; and wherein the methodfurther comprises, for each color-specific subpixel of the subset,receiving the input display value generated by the host computingdevice; applying the compensation data to the input display value toobtain a compensated display value; and wherein driving thecolor-specific subpixel based on the compensation data includes drivingthe color-specific subpixel with a compensated display signal based onthe compensated display value.
 9. The method of claim 8, whereinapplying the compensation data to the input display value includesproviding signal gain or signal attenuation to the input display valueto obtain the compensated display signal; and wherein the method furthercomprises: rebalancing the signal gain or signal attenuation provided tothe input display value to increase or maximize a quantity ofcolor-specific subpixels of the subset that have a target compensationvalue that does not introduce signal gain or signal attenuation.
 10. Themethod of claim 1, wherein the one or more display signals are sampledby a host computing device, and the compensation data is derived fromthe time-series of sampled values by the host computing device for eachcolor-specific subpixel of the subset; wherein the method furthercomprises, for each color-specific subpixel of the subset: receiving,from the host computing device, the compensation data at the graphicaldisplay device, applying the compensation data at the graphical displaydevice to an input display value received from the host computing deviceto obtain a compensated display value, and wherein driving thecolor-specific subpixel based on the compensation data includes drivingthe color-specific subpixel with a compensated display signal that isbased on the compensated display value.
 11. The method of claim 1,wherein the subset of the plurality of color-specific subpixels includesa first subset of color-specific subpixels corresponding to a firstwavelength or wavelength range; and wherein the plurality ofcolor-specific subpixels further includes a second subset ofcolor-specific subpixels corresponding to a second wavelength orwavelength range that differs from the first subset.
 12. The method ofclaim 11, further comprising: for each color-specific subpixel of thefirst subset, deriving the compensation data from the time-series ofsampled values based on a first subpixel wear model; and for eachcolor-specific subpixel of the second subset, deriving the compensationdata from the time-series of sampled values based on a second subpixelwear model that differs from the first subpixel wear model.
 13. Themethod of claim 12, wherein the first subpixel wear model defines afirst relationship between a magnitude of an accumulated value of thetime-series of sampled values for color-specific subpixels of the firstsubset and the compensation data to be derived from the time-series ofsampled values for the color-specific subpixels of the first subset; andwherein the second subpixel wear model defines a second relationship,that differs from the first relationship, between a magnitude of anaccumulated value of the time-series of sampled values forcolor-specific subpixels of the second subset and the compensation datato be derived from the time-series of sampled values for thecolor-specific subpixels of the second subset.
 14. The method of claim11, wherein the subset of the plurality of color-specific subpixelsfurther includes a third subset of color-specific subpixelscorresponding to a third wavelength or wavelength range that differsfrom the first subset and the second subset; and wherein the first,second, and third wavelength or wavelength ranges are selected from agroup comprising red, green, blue, white, infrared.
 15. A computingsystem, comprising: a graphical display device including: a displayregion having a plurality of color-specific subpixels spatiallydistributed across the display region; a data storage machine includinga buffer; and a logic machine programmed with instructions to: for eachcolor-specific subpixel of a subset of the plurality of color-specificsubpixels: receive compensation data from a host computing deviceconnected to the graphical display device via a communications link, thecompensation data being derived from a time-series of sampled valuesobtained from previously sampled display signals directed to thatcolor-specific subpixel, store the compensation data in the buffer,receive, via the communications link, an input display value generatedby the host computing device, apply the compensation data to the inputdisplay signal to obtain a compensated display value; and drive thecolor-specific subpixel with a compensated display signal based on thecompensated display value.
 16. The computing system of claim 15, furthercomprising: the host computing device, including: non-volatile storage;and a graphics processing unit programmed to: for each color-specificsubpixel of the subset: sample display signals driving thecolor-specific subpixel of the graphical display device to obtain atime-series of sampled values; combine the time-series of sampled valuesto obtain an accumulated value; store the accumulated value in thenon-volatile storage; derive the compensation data from the accumulatedvalue; and transmit the compensation data to the graphical displaydevice.
 17. The computing system of claim 15, wherein the subset of thecolor-specific subpixels includes a first subset of color-specificsubpixels corresponding to a first wavelength or wavelength range;wherein the plurality of color-specific subpixels includes a secondsubset of color-specific subpixels corresponding to a second wavelengthor wavelength range that differs from the first subset.
 18. Thecomputing system of claim 17, wherein the logic machine is furtherprogrammed with instructions to: for each color-specific subpixel of thesecond subset: receive second compensation data from the host computingdevice, the second compensation data for each color-specific subpixel ofthe second subset being derived from a time-series of sampled valuesobtained from one or more previously sampled display signals driving thecolor-specific subpixel, store the second compensation data in thebuffer, receive an input display value generated by the host computingdevice, apply the compensation data to the input display value to obtaina compensated display value; and drive the color-specific subpixel witha compensated display signal based on the compensated display value. 19.The computing system of claim 15, wherein the logic machine is furtherprogrammed with instructions to: for each color-specific subpixel of thesubset, apply the compensation data to the input display value to obtaina compensated display value by rebalancing signal gain or signalattenuation provided to the input display value to increase or maximizea quantity of color-specific subpixels of the subset that have a targetcompensation value that does not introduce signal gain or signalattenuation.
 20. A method of compensating for subpixel wear in agraphical display device having a plurality of color-specific subpixelsspatially distributed across a display region of the graphical displaydevice, the method comprising: for each color-specific subpixel of asubset of the plurality of color-specific subpixels: sampling one ormore display signals driving the color-specific subpixel to obtain atime-series of sampled values; combining the time-series of sampledvalues to obtain an accumulated value; storing, in non-volatile storage,the accumulated value; deriving a compensation data for thecolor-specific subpixel from the accumulated value; obtaining an inputdisplay value from a host computing device connected to the graphicaldisplay device; applying the compensation data to the input displayvalue to obtain a compensated display value; and driving thecolor-specific subpixel with a compensated display signal that is basedon the compensated display value; wherein the subset includes allcolor-specific subpixels of the display region having a definedwavelength or wavelength range that differs from another subset ofcolor-specific subpixels of the display region.